This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The objective of this study was to determine the prevalence of anti-norovirus (NoV), sapovirus (SaV) and Tulane virus (TV) antibodies in rhesus macaques of the Tulane National Primate Research Center (TNPRC) and evaluate the antigenic relationship between these viruses. A high prevalence of NoV (51-61%) and SaV (50-56%) binding antibodies and TV (69%) neutralizing antibodies were detected. Serum samples obtained during a human NoV outbreak and a multivalent anti-NoV hyperimmune serum were not able to neutralize TV infectivity. Conversely, low levels of cross-reactivity between the prototype TV and NoVs, but not between the TV and SaVs were detected by ELISA. These data indicate the preservation of some cross-reactive B-cell epitopes between the rhesus and human CVs. The high prevalence of human and rhesus CV-specific serum antibodies suggests the frequent exposure of colony macaques to enteric CVs including the possibility of CV transmission between human and NHP hosts.